Antibacterial oral composition

ABSTRACT

An antibacterial oral composition effective to promote oral hygiene containing an antibacterial antiplaque agent and an additive which reduces staining of dental surfaces without substantially diminishing the antibacterial and antiplaque activity of the agent. Bis-biguanido hexanes, such as chlorhexidine and alexidine, and quaternary ammonium salts, such as benzethonium chloride and cetyl pyridinium chloride, are typical examples of antibacterial agents. The antistain additive is a polymeric polyphosphonic compound, such as polyallyl bis-(phosphonomethylene) amine acid and salts thereof.

This is a divisional of application Ser. No. 629,749 filed Nov. 7, 1975,now U.S. Pat. No. 4,042,679, issued Aug. 16, 1977.

This invention relates to an antibacterial oral composition whichpromotes oral hygiene.

Cationic antibacterial materials are well known in the art. See, forinstance the section on "Quaternary Ammonium and Related Compounds" inthe article on "Antiseptics and Disinfectants" in Kirk-OthmerEncyclopedia of Chemical Technology 2nd edition (Vol. 2, p. 632-635),incorporated herein by reference. Cationic materials which possessantibacterial activity (i.e. are germicides) are used against bacteria.As bacteria are present in the oral cavity and lead to plaque formation,cationic antibacterial agents have been used in oral compositions tocounter plaque formation.

Among the most common of these antibacterial antiplaque quaternaryammonium compounds is benzethonium chloride, also known as Hyamine 1622or di-iso butyl (phenoxyethoxyethyl dimethyl benzyl ammonium chloride).In an oral preparation this material is highly effective in promotingoral hygiene by reducing formation of dental plaque and calculus.Reduction of plaque and calculus is generally accompanied by reductionin caries formation. Other cationic antibacterial agents of this typeare those mentioned, for instance, in U.S. Pat. Nos. 2,984,639;3,325,402; 3,703,583; and 3,431,208 and British Pat. No. 1,319,396.

Other antibacterial antiplaque quaternary ammonium compounds includethose in which one or two of the substituents on the quaternary nitrogenhas a carbon chain length (typically alkyl group) of some 8 to 20,typically 10 to 18, carbon atoms while the remaining substituents have alower number of carbon atoms (typically alkyl or benzyl group), such as1 to 7 carbon atoms, typically methyl or ethyl groups. Dodecyl trimethylammonium bromide, benzyl dimethyl stearyl ammonium chloride, cetylpyridinium chloride and quaternized 5-amino-1,3-bis(2-ethylhexyl)-5-methyl hexa hydro-pyrimidine are typical quaternaryammonium antibacterial agents.

Other types of cationic antibacterial agents which are desirablyincorporated in oral compositions to promote oral hygiene by reducingplaque formation are the amidines such as the substituted guanidinese.g. chlorhexidine and the corresponding compound, alexidine, having2-ethylhexyl groups instead of chlorophenyl groups and otherbis-biguanides such as those described in German patent application No.P 2,332,383 published Jan. 10, 1974, which sets forth the followingformula: ##STR1## in which A and A' signify as the case may be either(1) a phenyl radical, which as substituent can contain up to 2 alkyl oralkoxy groups with 1 up to about 4C-atoms, a nitro group or a halogenatom, (2) an alkyl group which contains 1 to about 12C-atoms, or (3)alicyclic groups with 4 to about 12C-atoms, X and X' as the case may bemay represent an alkylene radical with 1-3C-atoms, and z and z' are asthe case may be either zero or 1, R and R' as the case may be mayrepresent either hydrogen, an alkyl radical with 1 to about 12C-atoms oran aralkyl radical with 7 to about 12C-atoms, n is a whole number of 2to inclusively 12 and the polymethylene chain (CH₂)_(n) can beinterrupted by up to 5, ether, thioether, phenyl- or naphthyl groups;these are available as pharmaceutically suitable salts. Additionalsubstituted guanidines are: N'-(4-chlorobenzyl)-N⁵ -(2,4-dichlorobenzyl)biguanide; p-chlorobenzyl biguanide, 4-chlorobenzhydryl guanylurea;N-3-lauroxypropyl-N⁵ -p-chlorobenzyl biguanide;5,6-dichloro-2-guanidobenzimidazole; and N-p-chlorophenyl-N⁵-laurylbiguanide.

The long chain tertiary amines also possess antibacterial and antiplaqueactivity. Such antibacterial agents include tertiary amines having onefatty alkyl group (typically 12 to 18 carbon atoms) and 2poly(oxyethylene) groups attached to the nitrogen (typically containinga total of from 2 to 50 ethenoxy groups per molecule) and salts thereofwith acids and compounds of the structure: ##STR2## where R is a fattyalkyl group containing 12 to 18 carbon atoms and x, y and z total 3 orhigher, as well as salts thereof. Generally, cationic agents arepreferred for their antiplaque effectiveness.

The antibacterial antiplaque compound is preferably one which has aantibacterial activity such that its phenol coefficent is well over 50,more preferably well above 100, such as above about 200 or more for S.aureus; for instance the phenol coefficient (A.O.A.C.) of benzethoniumchloride is given by the manufacturer as 410, for S. aureus. Thecationic antibacterial agent will generally be a monomeric (or possiblydimeric) material of molecular weight well below 2,000, such as lessthan about 1,000. It is, however, within the broader scope of theinvention to employ a polymeric cationic antibacterial agent. Thecationic antibacterial agent is preferably supplied in the form of anorally acceptable salt thereof, such as the chloride, bromide, sulfate,alkyl sulfonate such as methyl sulfonate and ethyl sulfonate,phenylsulfonate, such as p-methylphenyl sulfonate, nitrate, acetate,gluconate, etc.

The cationic antibacterial agents and long chain tertiary amineantibacterial agents effectively promote oral hygiene, particularly byremoving plaque. However, their use has been observed to lead tostaining of dental surfaces or discoloration.

The reason for the formation of such dental stain has not been clearlyestablished. However, human dental enamel contains a high proportion(about 95%) of hydroxyapatite which includes Ca⁺² and PO₄ ⁻³ ions. Inthe absence of dental plaque additional Ca⁺² and PO₄ ⁻³, particularlyfrom saliva, can be deposited on the enamel and such deposits caninclude color bodies which ultimately stain the tooth enamel as acalcified deposit thereon. It can be that as the cationic or long chaintertiary amine antibacterial agents remove plaque they also denatureprotein from saliva in the oral environment and the denatured proteincan then act as a nucleating agent which is deposited on and stains ordiscolors tooth enamel.

Previously employed additives which reduced dental staining by cationicantibacterial antiplaque agents also generally reduced the activity ofthe antibacterial agents or its ability to act on dental plaque tomeasurable degrees. Further Victamide (also known as Victamine C) whichis the condensation product of ammonia with phosphorus pentoxideactually increases staining even in the absence of a cationicantibacterial antiplaque agent and it and other known phosphoruscontaining agents such as disodium-ethane-1-hydroxy-1,1,-diphosphonicacid salt precipitate in the presence of antibacterial agent such asbis-biguanido compound, thereby reducing the antiplaque effectiveness ofthe antibacterial agent.

It is an advantage of this invention that an anti-nucleating additive isprovided which prevents staining of dental enamel without substantiallyadversely affecting antibacterial and antiplaque activity of a cationicor long chain tertiary amine antibacterial agent. The anti-nucleatingadditives inhibit nucleation initiated by protein. Other advantages willbe apparent from consideration of the following disclosure.

In accordance with certain of its aspects this invention relates to anoral composition comprising an oral vehicle, a nitrogen-containingcationic or long chain tertiary amine antimicrobial agent and a watersoluble polymeric polyphosphomic compound selected from the groupconsisting of polymers having the recurring groups: ##STR3## wherein Xis selected from the group consisting of hydrogen and an orallyacceptable cation and Y is selected from the group consisting ofhydrogen and CH₃ and the unphosphonated recurring groups of compounds(1) and (3) have a molecular weight of at least about 3,500 andcompounds (2) and (4) have a molecular weight of at least about 2,000.Typical orally acceptable cations include alkali metal (e.g. sodium andpotassium), ammonium, C₁ -C₁₈ mono-, di and tri-ethanolammonium cations.

The end groups of the polymers are typically the phosphonated orunphosphonated monomers thereof.

The molecular weight of the polymers, their total recurring groups andthe unphosphonated forms thereof can be determined by various techniquesincluding measurement of intrinsic viscosity.

Antibacterial agents which are cationic or long chain amine germicideswhich may be employed in the practice of this invention are describedabove. They are typically employed in amounts such that the oral productcontains between about 0.001% and 15% by weight of the agent. Preferablyfor desired levels of antiplaque effect, the finished oral productcontains about 0.01 to about 5%, and most preferably about 0.025% to1.0% by weight of the agent. These amounts refer to the quantity of thefree base form of the agent.

The stain which generally occurs on dental enamel is unexpectedlyprevented when the polymeric polyphosphonic compound is employed. Thesematerials are anti-nucleating agents. In themselves (even in the absenceof antiplaque antibacterial agent) they are effective to reduceformation of dental calculus without unduly decalcifying enamel.However, not all anti-nucleating agents are effective to prevent stainby cationic antibacterial agents. For instance, Victamide actuallyincreases staining even in the absence of an antibacterial antiplaqueagent.

The polymeric polyphosphonated compounds having the recurring group##STR4## and orally acceptable salt thereof, are polymericpolyphosphonated polyethylene compounds wherein the polyethylenemolecular weight is at least about 3,500 and typically about 3,500 toabout 30,000 or more. Such polymers in the acid form have molecularweights of at least about 8,000 and typically about 8,060 to 61,500 ormore. In the form of the sodium salts the molecular weights are at leastabout 10,000 and typically about 10,600 to 79,500 or more.

A desirable polymeric polyphosphonated polyethylene is characterized ashaving a polyethylene molecular wieght of about 30,000, a molecularweight in its acid form of about 61,500 and a molecular weight in itssodium form of about 79,500. The polyphosphonate polymer of thepolyethylene Tenite 800 available from Eastman Kodak is such a polymer.It is made by reacting the polyethylene Tenite 800 with phosphoryltrichloride, hydrolyzing the product and converting to the salt form(e.g. sodium) if desired. Such a reaction is described by Anbar et al inthe "Journal of Dental Research", Volume 53, No. 4, pages 867-878(July-August, 1974).

Another desirable polymeric polyphosphonated polyethylene ischaracterized as having a polyethylene molecular weight of about 3,500,a molecular weight in its acid form of about 8,060 and a molecularweight in its sodium form of about 10,600. The polyphosphonate polymerof the polyethylene having an 11 methylene chain groups available fromUnion Carbide as DYDH is such a polymer. It is made in the same manneras the polyphosphonate polymer described above, except the polyethyleneDYDH is used in place of Tenite 800. A phosphonate group is present onevery 12th methylene carbon.

It is noteworthy that if the sodium salt polymer employed is thepolyphosphonate of polyethylene having a 10 methylene chain, in which aphosphonate group is present on every 11th methylene carbon, in whichthe polyethylene molecular weight is about 3,000 and the acid form ofwhich has a molecular weight of about 9270, the activity of a mouthwashcontaining an antibacterial antiplaque agent is diminished. When themolecular weight is greater, such activity is not diminished and staincan be reduced.

The polymeric allyl bis(phosphonomethylene) amine having the recurringgroup ##STR5## and salt thereof is made by direct reaction of allylamine, formaldehyde and phosphorous acid (H₃ PO₃) and converting to thesalt form (e.g. sodium) if desired. The reaction is described in the"Journal of Organic Chemistry", Moedritzer et al, Volume 31, page 1603et seq. (1966). A typical polymer is characterized by a molecular weightof the total polymer compound of at least about 2,000; the molecularweight of about 2,000 for the sodium salt being particularly desirable.

The polymeric acryloylphosphonic acid and methacryloylphosphonic acidhaving the recurring group ##STR6## wherein Y is hydrogen or methyl, andsalt thereof is made by phosphorylating an aqueous solution ofpolyacrylic or polymethacrylic acid with phosphoryl trichloride to forma rubber-like gel and converting to the salt form (e.g. sodium) ifdesired. The reaction is typically described in British Pat. No. 940,138of Henkel & Cie. A particularly desirable polymer is characterized by amolecular weight of the unphosphonated methacrylic polymer of about50,000; the degree of phosphonation being about 15-16%.

The polymeric polyallyl phosphonoacetate having the recurring group##STR7## and salt thereof is made by reacting by the Arbuzov reaction,ethyl chloracetate (ClCH₂ COOC₂ H₅) with triethyl phosphite (P(OC₂ H₅)₃)to form methylphosphonoacetate which on hydrolysis yields polyphosphonicacid ##STR8## This is then chlorinated (to form ##STR9## with thionylchloride (SO₂ Cl₂) in accordance with the reaction described in the"Journal of Organic Chemistry", Balsinger et al, Vol. 24, pages 434 etseq. (1959). Allyl alcohol (CH₂ ═CHCH₂ OH) is then reacted with thechlorinated phosphonoacetic acid to form the allylphosphonoacetatemonomer ##STR10## which is polymerized. The acid can be converted to thesalt form (e.g. sodium), if desired. A typical polymer is characterizedas having a total molecular weight of the polymeric compound of at leastabout 2,000; the molecular weight of about 2,000 for the sodium saltbeing particularly desirable.

The polymeric polyphosphonic compound which is most preferred is thepolyallyl bis(phosphonomethylene) amine and particularly the sodium saltthereof. Such a polymer in its sodium form most preferably has a totalmolecular weight of about 2,000.

The concentration of polymeric polyphosphonic compound in the oralcompositions can range widely, typically upward from about 0.01% byweight. There is no upper limit on the amount that can be utilizedexcept as dictated by cost or incompatibility with the vehicle.Generally, concentrations from about 0.01% to about 10% by weight areutilized. Preferably polymeric polyallylphosphonoacetate is used inamounts upward from about 0.2%. Oral compositions which in the ordinarycourse of usage could be accidentally ingested preferably contain lowerconcentrations of polymeric polyphosphonic compounds. Thus, a mouthwashin accordance with this invention preferably contains less than 3% byweight of polymeric polyphosphonic compound. Dentifrice compositions,topical solutions and prophylactic pastes, the latter to be administeredprofessionally, can contain from 0.01% to 10% by weight, preferably from0.1% to 5% by weight of polymeric polyphosphonic compound. Mostdesirably, the polymeric polyphosphoric compound is present in a molarexcess to the amount of antibacterial antiplaque agent (based on thefree base thereof), in order to best prevent staining by theantibacterial antiplaque agent.

In certain highly preferred forms of the invention the oral compositionmay be substantially liquid in character, such as a mouthwash or rinse.In such a preparation the vehicle is typically a water-alcohol mixture.Generally, the ratio of water to alcohol is in the range of from about1:1 to about 20:1 preferably from 3:1 to 20:1 and most preferably about17:3, by weight. The total amount of water-alcohol mixture in this typeof preparation is typically in the range of from about 70% to about99.9% by weight of the preparation. The pH of such liquid preparationsis generally in the range of from about 4.5 to about 10 and typicallyfrom about 5.5 to 9.7. The pH is preferably in the range of from about 7to about 9.2. It is noteworthy that the composition of the inventionpermits the use of the polymeric polyphosphic compound at a pH below 5without substantially decalcifying dental enamel.

Such liquid oral preparations may also contain a surface active agentand/or a fluorine-providing compound.

In certain other desirable forms of this invention, the oral compositionmay be substantially solid or pasty in character, such as a toothpowder,a dental tablet or a toothpaste or dental cream. Such compositionstypically have a pH like that of a mouthwash or mouthrinse. The vehicleof such solid or pasty oral preparations contains polishing material.Examples of polishing materials are water-insoluble sodiummetaphosphate, potassium metaphosphate, tricalcium phosphate, dihydratedcalcium phosphate, anhydrous dicalcium phosphate, calcium pyrophosphate,magnesium orthophosphate, trimagnesium phosphate, calcium carbonate,alumina, hydrated alumina, aluminum silicate, zirconium silicates,silica, bentonite, and mixtures thereof. Preferred polishing materialsinclude crystalline silica having particle sizes of up to 5 microns, amean particle size of up to 1.1 microns, and a surface area of up to50,000 cm² /gm. silica gel, complex amorphorus alkali metalaluminosilicate and hydrated alumina.

Alumina, particularly the hydrated alumina sold by Alcoa as C-333, whichhas an alumina content of 64.9% by weight, a silica content of 0.008%, aferric oxide content of 0.003%, and a moisture content of 0.37% at 110°C., and which has a specific gravity of 2.42 and a particle size suchthat 100% of the particles are less than 50 microns and 84% of theparticles are less than 20 microns, is particularly desirable.

When visually clear gels are employed, a polishing agent of collodialsilica, such as those sold under the trademark SYLOID as Syloid 72 andSyloid 74 or under the trademark SANTOCEL as Santocel 100 and alkalimetal aluminosilicate complexes are particularly useful, since they haverefractive indices close to the refractive indices of gellingagent-liquid (including water and/or humectant) systems commonly used indentifrices.

Many of the so called "water-insoluble" polishing materials are anionicin character and also include small amounts of soluble material. Thus,insoluble sodium metaphosphate may be formed in any suitable manner, asillustrated by Thorpe's Dictionary of Applied Chemistry, Volume 9, 4thEdition, pp. 510-511. The forms of insoluble sodium metaphosphate knownas Madrell's salt and Kurrol's salt are further examples of suitablematerials. These metaphosphate salts exhibit a minute solubility inwater, and therefore are commonly referred to as insolublemetaphosphates. There is present therein a minor amount of solublephosphate material as impurities, usually a few percent such as up to 4%by weight. The amount of soluble phosphate material, which is believedto include a soluble sodium tri-metaphosphate in the case of insolublesodium metaphosphate, may be reduced by washing with water if desired.The insoluble alkali metal metaphosphate is typically employed in powderform of a particle size such that no more than 1% of the material islarger than 37 microns.

The polishing material is generally present in amounts ranging fromabout 20% to about 99% by weight of the oral preparation. Preferably, itis present in amounts ranging from about 20% to about 75% in toothpaste,and from about 70% to about 99% in toothpowder.

In the preparation of toothpowders, it is usually sufficient to admixmechanically, e.g., by milling, the various solid ingredients inappropriate quantities and particle sizes.

In pasty oral preparations the combination of the antibacterialantiplaque agent and polymeric polyphosphonic compound should becompatible with the other components of the preparation. Thus, in atoothpaste, the liquid vehicle may comprise water and humectanttypically in an amount ranging from about 10% to about 90% by weight ofthe preparation. Glycerine, sorbitol, or polyethylene glycol may also bepresent as humectants or binders. Particularly advantageous liquidingredients comprise mixtures of water, glycerine and sorbitol.

In clear gels where the refractive index is an important consideration,about 3-30% by weight of water, 0 to about 80% by weight of glycerine,and about 20-80% by weight of sorbitol is preferably employed. A gellingagent, such as natural or synthetic gums or gum-like materials,typically Irish moss, sodium carboxymethylcellulose, methyl cellulose,or hydroxyethyl cellulose, may be employed. Other gelling agents whichmay be employed include gum tragacanth, polyvinylpyrrolidone and starch.They are usually present in toothpaste in an amount up to 10% by weight,preferably in the range of from about 0.5% to about 5%. The preferredgelling agents are methyl cellulose and hydroxyethyl cellulose. In atoothpaste or gel, the liquids and solids are proportioned to form acreamy or gelled mass which is extrudable from a pressurized containeror from a collapsible, e.g., aluminum or lead, tube.

The solid or pasty oral preparation which typically has a pH measured ona 20% slurry of about 4.5 to about 10, generally about 5.5 to about 9.7and preferably about 7 to about 9.2, may also contain a surface activeagent and/or a fluorine-providing compound.

It will be understood that, as is conventional, the oral preparationsare to be sold or otherwise distributed in suitably labelled packages.Thus a jar of mouthrinse will have a label describing it, in substance,as a mouthrinse or mouthwash and having directions for its use; and atoothpaste will usually be in a collapsible tube, typically aluminum orlined lead, or other squeeze dispenser for metering out the contents,having a label describing it, in substance, as a toothpaste or dentalcream.

In oral compositions such as mouthrinses and toothpastes, a surfactantis often present, e.g. to promote foaming. It will be understood that itis preferable to employ nonionic surfactants rather than their anioniccounterparts. Examples of water-soluble nonionic surfactants arecondensation products of ethyleneoxide with various compounds reactivetherewith having long hydrophobic chains (e.g. aliphatic chains of 12 to20 carbon atoms) which condensation products ("ethoxamers") havehydrophobic polyoxyethylene moieties, such as condensation products ofethylene oxide and fatty acids, fatty alcohols, fatty amides, includingalcohols such as sorbitan monostearate or polypropyleneoxide (that isPluronic materials).

In certain forms of this invention a fluorine-providing compound ispresent in the oral preparation. These compounds may be slightly solublein water or may be fully water-soluble. They are characterized by theirability to release fluoride ions in water and by substantial freedomfrom reaction with other compounds of the oral preparation. Among thesematerials are inorganic fluoride salts, such as soluble alkali metal,alkaline earth metal and heavy metal salts, for example, sodiumfluoride, potassium fluoride, ammonium fluoride, lead fluoride, a copperfluoride such as cuprous fluoride, zinc fluoride, a tin fluoride such asstannous fluoride or stannous chlorofluoride, barium fluoride, sodiumfluorosilicate, ammonium fluorosilicate, sodium fluorozirconate, sodiummonofluorophosphate, aluminum mono- and di-fluorophosphate, andfluorinated sodium calcium pyrophosphate. Alkali metal and tinfluorides, such as sodium and stannous fluorides, sodiummonofluorophosphate and mixtures thereof, are preferred.

The amount of the fluorine-providing compound is dependent to someextent upon the type of compound, its solubility, and the type of oralpreparation, but it must be a nontoxic amount. In a solid oralpreparation, such as a toothpaste or toothpowder, an amount of suchcompound which releases a maximum of 1% by weight of the preparation isconsidered satisfactory. Any suitable minimum amount of such compoundmay be used, but it is preferable to employ sufficient compound torelease from 0.005% to 1%, and preferably about 0.1% of fluoride ion.Typically, in the cases of alkali metal fluorides and stannous fluoride,this component is present in an amount up to 2% by weight, based on theweight of the preparation, and preferably in the range of from 0.05% to1%. In the case of sodium monofluorophosphate, the compound may bepresent in an amount up to 7.6% by weight, more typically 0.76%.

In a liquid oral preparation such as a mouthwash, the fluorine-providingcompound is typically present in an amount sufficient to release up to0.13%, preferably from 0.0013% to 0.1% and most preferably from 0.0013%to 0.05%, by weight, of fluoride ion.

Various other materials may be incorporated in the oral preparations ofthis invention. Examples are whitening agents, preservatives, silicones,chlorophyll compounds, and ammoniated material such as urea, diammoniumphosphate, and mixtures thereof. These adjuvants, where present, areincorporated in the preparations in amounts which do not substantiallyadversely affect the properties and characteristics desired.

Any suitable flavoring or sweetening material may also be employed.Examples of suitable flavoring constituents are flavoring oils, e.g.,oils of spearmint, peppermint, wintergreen, sassafras, clove, sage,eucalyptus, marjoram, cinnamon, lemon, and orange, and methylsalicylate. Suitable sweetening agents include sucrose, lactose,maltose, sorbitol, sodium cyclamate, perillartine, and saccharin.Suitably, flavor and sweetening agents may together comprise from 0.01%to 5% or more of the preparation.

Oral preparations of the invention may be prepared by dispersing theantibacterial antiplaque agent and the polymeric polyphosphonic compoundin an oral vehicle which typically includes water.

For instance, a mouthrinse or mouthwash may be prepared by mixingethanol and water with flavoring oil, nonionic surfactant, humectant,antibacterial antiplaque agent, such as benzethonium chloride orchlorhexidine, sweetener and color and then adding the polymericpolyphosphonic compound and additional water as desired. It is desirableto add the polymeric polyphosphonic compound after the other ingredientsare contacted with each other.

A toothpaste may be prepared by forming a gel with humectant, gum orthickener such as hydroxyethyl cellulose, sweetener and adding theretopolishing agent, flavor, antibacterial antiplaque agent, such asbenzethonium chloride or chlornexidine, and additional water, followedby addition of flavoring oil and the polymeric polyphoosphonic compound.It is preferable to add the polymeric polyphosphonic compound after theother components are contacted with each other. If sodium carboxymethylcellulose and a bis-biguanido hexane antibacterial agent are employed asthe gelling agent the procedure of either U.S. Pat. No. 3,842,168 orU.S. Pat. No. 3,843,779, modified by the inclusion of the polymericpolyphosphonic compound, is followed.

In the practice of this invention an oral composition such as amouthwash or toothpaste containing cationic or long chain amineantibacterial antiplaque agent in amount effective to promote oralhygiene and polymeric polyphosphonic compound in amount effective toreduce staining of dental surfaces otherwise resulting from the presenceof the antibacterial antiplaque agent is applied regularly to dentalenamel, preferably from about five times per week to about three timesdaily.

The following specific examples are further illustrative of the natureof the present invention; but it is understood that the invention is notlimited thereto. The compositions are prepared in the usual manner andall amounts of the various ingredients are by weight unless otherwiseindicated.

EXAMPLE 1

The following mouthwash(a) is prepared:

    ______________________________________                                                             Parts                                                    ______________________________________                                        Flavored alcohol       15                                                     Pluronic F-108         3                                                      Glycerine              10                                                     Benzethonium chloride  0.1                                                    Sodium saccharin       0.03                                                   Polyallyl bis(phosphono-                                                      methylene) amine       0.1                                                    Water                  Q.S. to 100                                            pH 7.7                                                                        ______________________________________                                    

The polyallyl bis(phosphonomethylene) amine contains the recurring group##STR11## the molecular weight of the sodium salt of which is about2,000.

The several ingredients are mixed with polyallyl bis(phosphonomethylene)amine with about 10 parts of water being withheld until the end.

Additional mouthwashes are prepared with the following modifications:

    ______________________________________                                                 Parts of     Parts of Polyallyl                                               Benzethonium Bis(phosphonomethylene)                                 Mouthwash                                                                              Chloride     Amine            pH                                     ______________________________________                                        (b)      0.075        0.15             8.9                                    (c)      0.075        0.2              9.5                                    (d)      0.15         0.4              9.7                                    ______________________________________                                    

All compositions are clear without visible evidence of precipitation.

The antiplaque activity and staining levels of the mouthwashes of thesame pH and composition except for the absence of the polyallylbis(phosphonomethylene) amine are determined.

Tests are made of the ability of the compositions to inhibit in vitroplaque formation by allowing plaque to form (for 48 hours at 37° C.) onthe surfaces of cleaned and pumiced teeth in a preinoculated sucrosebroth containing Strep mutans. The pre-grown plaque is then immersed inthe test composition and rinsed with a buffer 1-5 times for 1 minuteeach. The teeth carrying the plaque are then transferred to a sucrosebroth containing 1 mg/100 ml of bromocresol green indicator andincubated at 37° C. anaerobically for 18 hours. An antibacterialcompound is considered effective if the indicator does not turn yellow(which begins when pH reaches 5.5) and there is no further growth of theplaque as judged by the increase in turbidity. It is found that on theclean teeth, plaque formation and plaque growth are effectivelyinhibited.

The tooth staining characteristics of the composition are tested byslurrying hydroxylapatite with salivary protein and acetaldehyde and apH 7 phosphate buffer. The mixture is shaken at 37° until a light browncolor is formed, which colored material is separated.

Color levels are determined on a Gardner Color Difference Meter beforeand after the test composition is applied to the colored material.

The antiplaque results are as follows:

    ______________________________________                                                                Inhibition of                                         Composition             Three Day                                             Polymeric    Active After   Plaque Growth &                                   Phosphosphonate                                                                            Indicated No.  Acid Production                                   Presence     Of Rinses With Buffer                                                                        Growth   Acid                                     ______________________________________                                        (a) no           5              yes    yes                                    (a) yes          5              yes    yes                                    (b) no           5              yes    yes                                    (b) yes          5              yes    yes                                    (c) no           5              yes    yes                                    (c) yes          5              yes    yes                                    (d) no           5              yes    yes                                    (d) yes          5              yes    yes                                    ______________________________________                                    

Thus, it is observed that the polyallyl bis(phosphonomethylene) aminedoes not reduce the in vitro antiplaque activity of benzethoniumchloride.

The antistain results are as follows for the mouthwashes of theinvention and corresponding mouthwashes from which the polymericpolyphosphonic compound is omitted:

    ______________________________________                                        Mouthwash                                                                     Polymeric                                                                     Polyphosphonic               Reflectance                                      Compound Presence Reflectance                                                                              Difference                                       ______________________________________                                        (a)    no             46                                                      (a)    yes            51         5                                            (b)    no             57                                                      (b)    yes            72         15                                           (c)    no             54                                                      (c)    yes            64         10                                           (d)    no             51                                                      (d)    yes            68         17                                           ______________________________________                                    

In the cases of mouthwashes (b), (c) and (d), each with and withoutpolymeric polyphosphonic compound additive, the pH is adjusted to 8 withhydrochloric acid after preparation in order to render the pH valuesuniform.

Thus, it is observed that the polyallyl bis(phosphonomethylene) amninesubstantially reduces staining by benzethonium chloride particularly ata pH of about 8.

EXAMPLE 2

Mouthwashes similar to those of Example 1 are prepared except thatchlorhexidine diacetate and chlorhexidine digluconate in amountcorresponding to 0.1 part of chlorhexidine free base and the polyallylbis(phosphonomethylene) amine are present and the pH is adjusted below8. These mouthwashes are active against plaque in vitro and inhibitplaque growth and acid as do the corresponding mouthwashes without thepolyallyl bis(phosphonomethylene) amine. In the antistain test the stainlevels when the polymeric polyphosphonic compound is present is lessthan the stain level when it is absent.

Alexidine also maintains its antiplaque effect with reduced staining inthe presence of the polyallyl bis(phosphonmethylene) amine, as do otherantibacterial antiplaque agents including cetyl pyridinium chloride anda C₁₂ -C₁₈ alkyl tertiary amine of the formula: ##STR12##

EXAMPLE 3

Mouthwashes corresponding to those of Example 1 with the indicatedamounts of benzethonium chloride and the indicated amounts of particularpolymeric polyphosphonic compound in place of polyallylbis(phosphonomethylene) amine are prepared:

    ______________________________________                                        Parts of  Parts of Polymeric                                                                           Polymeric                                            Benzethonium                                                                            Polyphosphonic Polyphosphonic                                       Choloride Compound       Compound    pH                                       ______________________________________                                        (a)   0.1     0.1            *         9.2                                    (b)   0.075   0.15           *         9.4                                    (c)   0.075   0.2            *         9.5                                    (d)   0.15    0.4            *         9.4                                    (e)   0.1     0.1            **        8.4                                    (f)   0.075   0.15           **        7.9                                    (g)   0.075   0.2            **        8.3                                    (h)   0.15    0.4            **        8.0                                    (i)   0.1     0.1            ***       7.7                                    (j)   0.075   0.2            ***       8.5                                    (k)   0.15    0.4            ***       8.4                                    (l)   0.1     0.1            ****      8.4                                    (m)   0.075   0.15           ****      8.5                                    (n)   0.075   0.2            ****      8.4                                    (o)   0.15    0.4            ****      8.5                                    ______________________________________                                         *is a polymeric polyphosphonic compound having the                            ##STR13##                                                                     wherein the polyethylene molecular weight is about 3,500 and the total        molecular height is about 10,600.                                             **is the polymeric polyphosphonic compound having the                         ##STR14##                                                                     wherein the polyethylene molecular weight is about 30,000 and the total       molecular weight is about 79,500.                                             ***is the polymeric polyphosphonic compound having                            ##STR15##                                                                     wherein the unphosphonated molecular weight is about 50,000 and the degre     of phosphonation is about 15.52%.                                             ****is the polymeric polyphosphonic compound having                           ##STR16##                                                                     wherein the polymeric molecular weight is about 2,000. These mouthwashes      are active against plaque in vitro and inhibit three day plaque growth an     acid as do the corresponding mouthwashes without the polymeric                polyphosphonic compound.                                                 

The following results are observed in the antistain test for themouthwashes and corresponding mouthwashes from which the polymericpolyphosphonic compound is omitted:

    ______________________________________                                        Mouthwash                                                                     Polymeric Polyphosphonic      Reflectance                                     Compound Presence  Reflectance                                                                              Difference                                      ______________________________________                                        (a)  No                46                                                     (a)  Yes               57         11                                          (b)  No                57                                                     (b)  Yes               57         0                                           (c)  No                54                                                     (c)  Yes               57         3                                           (d)  No                51                                                     (d)  Yes               57         6                                           (e)  No                46                                                     (e)  Yes               50         4                                           (f)  No                57                                                     (f)  Yes               57         0                                           (g)  No                54                                                     (g)  Yes               57         3                                           (h)  No                51                                                     (h)  Yes               59         8                                           (i)  No                46                                                     (i)  Yes               46         0                                           (j)  No                54                                                     (j)  Yes               57         3                                           (k)  No                51                                                     (k)  Yes               63         12                                          (l)  No                46                                                     (l)  Yes               46         0                                           (m)  No                57                                                     (m)  Yes               57         0                                           (n)  No                54                                                     (n)  Yes               60         6                                           (o)  No                51                                                     (o)  Yes               55         4                                           ______________________________________                                    

In those situations in which no substantial reflectance difference isobserved (b, f, i, l and m) the pH is not adjusted after preparation ofthe mouthwashes. In all other situations, the pH was adjusted to 8.0 andstain is reduced.

EXAMPLE 3

The following antiplaque reduced staining toothpastes are prepared:

    ______________________________________                                                         Parts    Parts                                               ______________________________________                                        Hydrated Alumina   30         30                                              Glycerine          16         16                                              Sorbitol (70%)     6          6                                               Pluronic F-108     3          3                                               Hydroxyethyl cellulose                                                                           1.2        1.2                                             Benzethonium chloride                                                                            0.5        --                                              Chlorhexidine digluconate                                                      (20%)             --         4.725                                           Polyallyl bis(phosphono-                                                       methylene) amine                                                              (of Example 1)    2          2                                               Sodium saccharin   0.17       0.17                                            Flavor             0.8        0.8                                             Water              Q.S. to 100                                                                              Q.S. to 100                                     ______________________________________                                    

It will be apparent to one skilled in the art that modifications of theabove examples may be made thereto.

I claim:
 1. An oral composition comprising an oral vehicle, an amidineantibacterial antiplaque agent tending to stain dental surfaces and awater soluble polymeric polyphosphonic compound having the recurringgroup: ##STR17## wherein X is selected from the group consisting ofhydrogen and an orally acceptable cation and said compound antistainadditive has a molecular weight of at least about 2,000.
 2. The oralcomposition of claim 1 wherein said polymeric polyphosphonic compound isin the form of its sodium salt and has a molecular weight of about2,000.
 3. The oral composition of claim 1 wherein said antibacterialantiplaque agent is present in amount to provide about 0.001% to about15% by weight based on the free base form of said agent and saidpolymeric polyphosphonic compound is present in amount of about 0.01% toabout 10% by weight.
 4. The oral composition of claim 3 whereim saidantibacterial antiplaque agent is present in amount of about 0.01% toabout 5% by weight based on the free base form of said agent and saidpolymeric polyphosphonic compound is present in a molar excess to saidagent.
 5. The oral composition of claim 3 wherein said antibacterialantiplaque agent is a substituted guanidine.
 6. The oral composition ofclaim 5 wherein said antibacterial antiplaque agent is apharmaceutically acceptable water soluble salt of an agent selected fromthe group consisting of chlorhexidine and alexidine.
 7. The oralcomposition of claim 6 wherein said antibacterial antiplaque agent is apharmaceutically acceptable water soluble salt of chlorhexidine.
 8. Theoral composition of claim 1 wherein said vehicle is an aqueous-alcoholand said composition is a mouthwash of pH of about 4.5 to about
 10. 9.The oral composition of claim 1 wherein said vehicle comprises a liquidvehicle and a gelling agent and a dentally acceptable polishing materialis present and said composition is a toothpaste of pH of about 4.5 toabout 10.